Handheld electronic devices, such as mobile phones, cameras and personal digital assistants (PDAs), offer a multitude of services and functions. For example, with the development of wireless technologies, many handheld devices are capable of connecting a user to a wireless network, such as the Internet, and allowing the user to send and receive information to and from other users via the wireless network. Moreover, many handheld devices can load and run software applications that allow the user to perform computing tasks.
While handheld devices can offer performance and versatility, the available services can sometimes be awkward to use because of device's size. Of particular concern is data entry, e.g., inputting text for an electronic message. Most handheld devices lack the space to provide a full keyboard for entering data and instead utilize several known techniques to allow the user to create words or number patterns. Nevertheless, each technique has its disadvantages.
For example, mobile phones typically provide a conventional number-key pad where each number key, i.e., key 2-9, is associated with three to four alphanumeric characters. By pressing specific keys, the user can form words. One method for creating words using the number-key pad uses a prediction algorithm that relies on an electronic dictionary of common words to predict a word based on the key(s) pressed. This technique, referred to as the T-9 technique, allows the user to tap a key, and a input value selection module in the device checks the dictionary to resolve ambiguities between the letters associated with the tapped key. Although the T-9 technique is a single-tap method that can allow fast data entry, it is not intuitive and can be deficient when two or more words are formed by the same sequence of tapped keys. In that instance, the T-9 technique cannot disambiguate between the words themselves and the user must resolve the ambiguity.
Another word forming technique using the number-key pad is referred to as multi-tapping. In multi-tapping, the user enters a particular letter by pressing the number key associated with the letter at least one time to scroll to the desired letter. Once the desired letter is found, e.g., displayed on the screen, the user must wait until the selection is committed and the letter is inputted before proceeding to the next letter. While multi-tapping allows the user to form words without ambiguity, it is time-consuming and awkward.
Other handheld devices, such as PDAs, can display a full keyboard on a touch screen, and the user selects letters by touching or tapping on the touch screen with a stylus. In other similar devices, a full miniature keyboard is provided in the device itself. In both instances, the size of the displayed and physical keyboard is reduced to accommodate the space limitations. Because the keys are small, they are difficult to see or press, making text entry awkward and slow as well as error prone.
Other text entry techniques exist but suffer from the same and other shortcomings described above. Most of these techniques, in addition to being awkward and slow, are not intuitive and/or require the user to spend much time practicing in order to become somewhat proficient.